1. Field of the Invention
The present invention relates to a fixing device for fixing an image formed on a surface of a sheet, and to an image forming apparatus provided with the fixing device, and to a sheet conveying device.
2. Description of the Related Art
Conventionally, an image forming apparatus, such as a printer, a copying machine, a facsimile, and a composite machine constituted by functionally combining these, includes a fixing device for fixing a toner image formed on the surface of a transfer sheet to the transfer sheet. The fixing device includes a fixing roller pair consisting of a heating roller for melting a toner, and a pressing roller made press contact with the heating roller. Further, there is known an image forming apparatus mounted with a fixing device having a separating pawl whose tip part is made press contact with the surface of at least one of the fixing roller pair (for example, see Japanese Patent Laid-Open No. 2005-099676, Japanese Patent Laid-Open No. 11-184300, Japanese Patent Laid-Open No. 2002-082564, Japanese Patent Laid-Open No. 06-032516, Japanese Patent Laid-Open No. 2002-287554).
The separating pawl is arranged on a downstream side in the conveying direction of the sheet with respect to the fixing roller pair, and prevents the sheet from being kept stuck to the fixing roller pair by being made press contact with the surface of one of the heating roller and the pressing roller.
Further, for the fixing of the separating pawl, there is adopted a technique by which the trailing edge of the separating pawl is stuck and fixed to a thin-walled bracket and the like, and the thin-walled bracket is fixed to a device main body or a unit-like fixing device with screws.
However, in the fixing device constituted as described above, since the trailing edge of the separating pawl is stuck and fixed to the thin-walled bracket and the like, the sticking work of the separating pawl is needed separately from the mounting work of the thin-walled bracket. This causes the number of components of the fixing device to be increased, and causes the mounting work of the components to be complicated, resulting in a problem that the fixing device is inferior in terms of versatility.
Further, it is necessary to prepare the thin-walled bracket for holding the separating pawl, which corresponds to the length, width, wall thickness and the like, of the separating pawl. For this reason, a plurality of kinds of separating pawls, thin-walled brackets and the like, need to be prepared for every model and the like of fixing devices so as to correspond to each other, which results in a problem that the control of inventory including molding dies is very troublesome.
Further, in the case where the separating pawl is adapted to be held by the thin-walled bracket, it is necessary to exchange the whole thin-walled bracket when the separating pawl is exchanged. For this reason, even when the separating pawl needs to be exchanged during the maintenance work, it is difficult to exchange the separating pawl on the spot. As a result, the maintenance work (exchanging work) needs to be performed again after component procurement or the like. This causes a problem that the versatility is also lowered from a viewpoint of the maintenance.